Sizing composition for sheet molding compound roving

ABSTRACT

An aqueous glass fiber sizing composition that includes a polymeric film forming component, at least one silane coupling agent, and one or more lubricants is provided. The polymeric film forming component of the sizing composition includes a silanated polyvinyl acetate, an epoxidized polyvinyl acetate, and a modified epoxy emulsion. In preferred embodiments, the film formers are present in the sizing composition in ratios of 70:25:5, 50:25:25, or 63:18:18 of silanated polyvinyl acetate, epoxidized polyvinyl acetate, and modified epoxy emulsion respectively. Fibers sized with the sizing composition in a sheet molding compound process have improved wet-out characteristics.

TECHNICAL FIELD AND INDUSTRIAL APPLICABILITY OF THE INVENTION

The present invention relates generally to size compositions for glassfibers, and more particularly, to size compositions that include a filmforming polymer component formed of a silanated polyvinyl acetate, anepoxidized polyvinyl acetate, and a modified epoxy emulsion.

BACKGROUND OF THE INVENTION

Glass fibers are useful in a variety of technologies. For example, glassfibers are used as reinforcements in polymer matrices to form glassfiber reinforced plastics or composites. Glass fibers have been used inthe form of continuous or chopped filaments, strands, rovings, wovenfabrics, non-woven fabrics, meshes, and scrims to reinforce polymers.Glass fibers are commonly used as reinforcements in polymer matrices toform glass fiber reinforced plastics or composites because they providedimensional stability as they do not shrink or stretch in response tochanging atmospheric conditions. In addition, glass fibers have hightensile strength, heat resistance, moisture resistance, and high thermalconductivity.

Typically, glass fibers are formed by attenuating streams of a moltenglass material from a bushing or orifice. An aqueous sizing compositioncontaining a film forming polymer, a coupling agent, and a lubricant istypically applied to the fibers after they are drawn from the bushing toprotect the fibers from breakage during subsequent processing and toimprove the compatibility of the fibers with the matrix resins that areto be reinforced. After the sizing composition has been applied, thesized fibers may be gathered into separate strands and wound to producea glass fiber package. The glass fiber package may then be heated toremove water and deposit the size as a residue lightly coating thesurface of the glass fiber. Multiple numbers of the resulting driedglass fiber packages may be consolidated and wound onto a spool referredto as a roving doff or package. The roving package is composed of aglass strand with multiple bundles of glass fibers.

Reinforcement rovings may be used in a sheet molding compound (SMC)process. In an SMC production process, a layer of a polymer film, suchas an unsaturated polyester resin or vinyl ester resin premix, ismetered onto a plastic carrier sheet that has a non-adhering surface.Chopped glass fiber roving bundles are then deposited onto the polymerfilm and a second, non-adhering carrier sheet containing a second layerof polymer film is positioned onto the first sheet such that the secondpolymer film contacts the chopped glass bundles and forms a sandwichedmaterial. This sandwiched material is then kneaded to distribute thepolymer resin matrix and glass fiber bundles throughout the resultantSMC material, which may then be rolled for later use in a moldingprocess.

In the production of SMC compounds, it is desirable that the choppedglass fiber bundles contact the polymeric matrix material. One measureof this contact is referred to as wetting, which is a measure of howwell the glass bundles are encapsulated by the matrix SMC resinmaterial. It is desirable to have the glass bundles completely wet withno dry glass. Incomplete wetting during this initial processing canadversely affect subsequent processing as well as the surfacecharacteristics of the final composite. For example, poor wetting mayresult in poor molding characteristics of the SMC, resulting in lowcomposite strengths and surface defects in the final molded part. TheSMC manufacturing process throughput, such as lines speeds andproductivity, are limited by how well and how quickly the roving choppedbundles can be completely wet.

Thus, there exists a need in the art for a sizing composition thatimproves wetting, and correspondingly the SMC production rate and thephysical properties of the molded composite part.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a sizing compositionthat contains a film forming polymer component, a silane coupling agent,and a lubricant. The film forming polymer component is formed of asilanated polyvinyl acetate, an epoxidized polyvinyl acetate, and amodified epoxy emulsion. Non-limiting examples of modified epoxyemulsions include amine-modified emulsions and epoxy ester emulsions.The film formers are preferably present in the sizing composition in aratio of 70:25:5, 50:25:25, or 63:18:18 of silanated polyvinyl acetate,epoxidized polyvinyl acetate, and modified epoxy emulsion respectively.The sizing composition may include a pH adjusting agent such as aceticacid, citric acid, sulfuric acid, or phosphoric acid to adjust the pH.Preferably, the sizing composition has a pH of from 3.0–7.0.

It is another object of the present invention to provide a reinforcingfiber product that contains one or more strands of a reinforcing fibermaterial at least partially coated with a sizing composition thatcontains a silanated polyvinyl acetate, an epoxidized polyvinyl acetate,a modified epoxy emulsion, a silane coupling agent, and a lubricant.Preferably the silanated polyvinyl acetate, the epoxidized polyvinylacetate, and the modified epoxy emulsion are present in the sizecomposition in a ratio of 70:25:5, 50:25:25, or 63:18:18 of silanatedpolyvinyl acetate, epoxidized polyvinyl acetate, and modified epoxyemulsion respectively. Suitable examples of the modified epoxy emulsioninclude amine-modified emulsions and epoxy ester emulsions. Thereinforced fiber product may be in the form of a roving.

It is a further object of the present invention to provide a reinforcedcomposite article formed of a plurality of glass fibers sized with asizing composition that contains a silanated polyvinyl acetate, anepoxidized polyvinyl acetate, a modified epoxy emulsion, a silanecoupling agent, and a lubricant. The silanated polyvinyl acetate, theepoxidized polyvinyl acetate, and the modified epoxy emulsion arepreferably present in the size composition in a ratio of 70:25:5,50:25:25, or 63:18:18 of silanated polyvinyl acetate, epoxidizedpolyvinyl acetate, and modified epoxy emulsion respectively.Non-exclusive examples of modified epoxy emulsions includeamine-modified emulsions and epoxy ester emulsions. The reinforcedcomposite may be in the form of an exterior body part or a structuralbody part of an automobile.

It is yet another object of the present invention to provide a method offorming a reinforced composite article that includes depositing choppedglass fibers at least partially coated with a sizing composition thatcontains a silanated polyvinyl acetate, an epoxidized polyvinyl acetate,a modified epoxy emulsion, a silane coupling agent, and a lubricant on afirst polymer film, positioning a second polymer film on the choppedglass fibers to form a sandwiched material, and molding the sandwichedmaterial into a molded composite part. Preferably, the silanatedpolyvinyl acetate, the epoxidized polyvinyl acetate, and the modifiedepoxy emulsion are present in the size composition in a ratio of70:25:5, 50:25:25, or 63:18:18 of silanated polyvinyl acetate,epoxidized polyvinyl acetate, and modified epoxy emulsion respectively.Suitable examples of modified epoxy emulsions include, but are notlimited to, amine-modified emulsions and epoxy ester emulsions.

It is an advantage of the sizing composition that the sizing compositionprovides improved wetting characteristics and thus fewer dry fibers in asheet molding compound material. Improved wetting characteristicsresults in greater productivity in-line, a reduction in the number ofdefects during the molding of a composite part, and a reduction inmanufacturing costs.

The foregoing and other objects, features, and advantages of theinvention will appear more fully hereinafter from a consideration of thedetailed description that follows.

DETAILED DESCRIPTION AND PREFERRED EMBODIMENTS OF THE INVENTION

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which the invention belongs. Although any methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of the present invention, the preferred methodsand materials are described herein. It is to be noted that the phrases“size composition”, “sizing composition”, and “size” are usedinterchangeably herein.

The present invention relates to improved sizing compositions for fibersthat may be used in a sheet molding compound (SMC) process. The sizingcomposition contains a film forming polymer component, at least onecoupling agent, and one or more lubricants. Conventional additives mayalso be present in the sizing composition.

The film forming polymer component of the sizing composition contains acombination of a silanated polyvinyl acetate, an epoxidized polyvinylacetate, and a modified epoxy emulsion. Examples of suitable silanatedpolyvinyl acetates include, but are not limited to, National Starch25-1037 (Vinamul Polymers) and Franklin Duracet 660 (FranklinInternational). Non-limiting examples of suitable epoxidized polyvinylacetates for use in the sizing composition include HB Fuller PD-166 (HBFuller Company) and National Starch 25-1971 (Vinamul Polymers).Non-exclusive examples of modified epoxy emulsions that may be includedin the size composition include AOC EE-732 (AOC), an amine-modifiedepoxy emulsion, and Neoxil 961 (DSM Italia), an epoxy ester emulsion.The film formers are preferably present in the sizing composition in aratio of 70:25:5, 50:25:25, or 63:18:18 of silanated polyvinyl acetate,epoxidized polyvinyl acetate, and modified epoxy emulsion respectively.

The sizing composition also contains at least one coupling agent.Preferably, at least one of the coupling agents is a silane couplingagent. Silane coupling agents function to enhance the adhesion of thefilm forming polymers to the glass fibers and to reduce the level offuzz, or broken fiber filaments, during subsequent processing. Examplesof silane coupling agents which may be used in the present sizecomposition may be characterized by the functional groups amino, epoxy,vinyl, methacryloxy, azido, ureido, and isocyanato. Suitable silanecoupling agents for use in the size include, but are not limited to,γaminopropyltriethoxysilane (A-1100),n-trimethoxy-silyl-propyl-ethylene-diamine (A-1120),γ-methacryloxypropyltrimethoxysilane (A-174),γ-glycidoxypropyltrimethoxysilane (A-187), methyl-trichlorosilane(A-154), methyl-trimethoxysilane (A-163),γ-mercaptopropyl-trimethoxy-silane (A-189),bis-(3-[triethoxysilyl]propyl)tetrasulfane (A-1289),γ-chloropropyl-trimethoxy-silane (A-143), vinyl-triethoxy-silane(A-151), vinyl-tris-(2-methoxyethoxy)silane (A-172),vinylmethyldimethoxysilane (A-2171), vinyl-triacetoxy silane (A-188),octyltriethoxysilane (A-137), methyltriethoxysilane (A-162), andmethyltrimethoxysilane (A-1630). All of the silane couplings agentslisted herein are available from GE Silicones. The coupling agent may bepresent in the sizing composition in an amount of from about 0.05% toabout 0.20% active solids, and more preferably in an amount of fromabout 0.08 to about 0.15% active solids.

The sizing composition also contains at least one lubricant tofacilitate manufacturing. Any conventional lubricant may be incorporatedinto the size composition. Non-exclusive examples of lubricants suitablefor use in the size composition include, but are not limited to,partially amidated long-chain polyalkylene imines such as Emery 6760L(Cognis), ethyleneglycol oleates, ethoxylated fatty amines, glycerine,emulsified mineral oils, organopolysiloxane emulsions, a stearicethanolamide such as Lubesize K-12 (AOC), and water-solubleethyleneglycol stearates such as polyethyleneglycol monostearate,butoxyethyl stearate, and polyethylene glycol monooleate. The lubricantmay be present in an amount of from about 0.025 to about 0.010% activesolids.

In addition, the size composition may optionally include a pH adjustingagent, such as acetic acid, citric acid, sulfuric acid, or phosphoricacid to adjust the pH level of the composition. The pH may be adjusteddepending on the intended application, or to facilitate thecompatibility of the ingredients of the size composition. Preferably,the sizing composition has a pH of from 3.0–7.0, and even morepreferably, a pH of from 3.5–4.5.

The sizing composition of the present invention may optionally containconventional additives such as anti-static agents, dyes, oils, fillers,thermal stabilizers, biocides, anti-foaming agents, anti-oxidants, dustsuppression agents, wetting agents, and/or any other conventionaladditives. The amount of additives present in the size composition ispreferably not in excess of approximately 5% of the total weight of thesize.

The balance of the size composition is composed of water. In particular,water may be added to dilute the aqueous sizing composition to aviscosity that is suitable for its application to glass fibers. Thesizing composition may contain up to approximately 95% water.

Three exemplary sizing compositions according to the present inventionare set forth in Table 1.

TABLE 1 Inventive Inventive Inventive Sizing Sizing Sizing CompositionComposition Composition 1 2 3 70/25/5 50/25/25 63/18/18 % Active TargetTarget Target Material Solids Weight (g) Weight (g) Weight (g) AceticAcid 100.0 67.8 73.6 67.8 A-1100⁽¹⁾ 58.0 116.8 126.8 116.8 National 55.26996.2 5425.6 6329.6 Starch 25-1037⁽²⁾ PD-166⁽³⁾ 54.7 2523.3 2739.61850.1 AOC 32.4 851.2 4621.0 3120.6 EE-732⁽⁴⁾ Emery 12.5 336.0 364.8336.0 6760L⁽⁵⁾ Water 0.0 69108.7 66648.6 68179.1 (Total Used) FinalWeight 80000 80000 80000 Target Mix 0.070 0.076 0.070 Solids⁽¹⁾γ-aminopropyltriethoxysilane (GE Silicones) ⁽²⁾silanated polyvinylacetate (Vinamul Polymers) ⁽³⁾epoxidized polyvinyl acetate (HB FullerCompany) ⁽⁴⁾modified epoxy resin emulsion (AOC) ⁽⁵⁾partially amidatedlong-chain polyalkylene imine (Cognis)

The size composition may be made by first admixing the coupling agent,the acid, and the film formers with agitation to form a main mixture. Ifnecessary, the main mixture is adjusted to a pH of approximately3.5–7.0. The lubricant is diluted with water to form a lubricant premix,which is added to the main mixture with agitation. Water is then addedin an amount to achieve the appropriate concentration and control themix of solids.

The size composition may be applied to strands of glass formed byconventional techniques such as by drawing molten glass through a heatedbushing to form substantially continuous glass fibers. Any type ofglass, such as A-type glass, C-type glass, E-type glass, S-type glass,E-CR glass, or modifications thereof, is suitable for use as the fibermaterial. For example, in one modification of E-type glass, the boronoxide is replaced by magnesium oxide. Such a glass is commerciallyavailable from Owens Coming Fiberglass Corporation under the trade nameAdvantex®. Alternatively, the sizing composition may be applied tostrands of one or more synthetic polymers such as polyester, polyamide,aramid, and mixtures thereof. The polymer strands may be used alone asthe reinforcing fiber material, or they can be used in combination withglass strands such as those described above. Carbon fibers may also beused.

The size composition is preferably applied to the fibers and dried suchthat the size is present on the fibers in an amount of from about 1.0 toabout 2.25% based on the total weight of the fibers. This can bedetermined by the loss on ignition (LOI) of the fiber rovings, which isthe reduction in weight experienced by the fibers after heating them toa temperature sufficient to burn or pyrolyze the size from the fibers.To achieve the desired solids content on the fibers, the amount of wateradded to dilute the size mixture may be varied. The size composition maybe applied to fibers having a diameter of from about 11 to about 20microns, with fibers of from about 13 to about 16 microns in diameterbeing more preferred. The mix solids content of the size may range fromabout 5 to about 15%.

The sizing composition may be applied to the fibers in any conventionalmanner, such as by spraying the size composition onto the fibers or bydrawing the fibers to be sized across a rotating or stationary roll wetwith the sizing composition. The size composition is preferably appliedto the fibers in an amount sufficient to provide the fibers with amoisture content of from about 5% by weight to about 15% by weight.

Fibers sized with the above-described sizing composition may beadvantageously employed as reinforcements in a sheet molding compound(SMC), such as, for example, to form exterior body parts and structuralbody parts of automobiles. For example, the sizing composition may beapplied to glass fibers in any conventional manner. The sized glassfibers may then be gathered into separate strands and wound to produce aglass fiber package. Next, the package may be heated to a temperaturehigh enough to remove water from the package but not cure the sizingcomposition. Multiple numbers of the dried glass fiber packages may bewound onto a spool referred to as a roving doff or package (roving) andstored for later use or chopped for immediate use.

The chopped glass fibers may be placed onto a layer of a polymer film,such as an unsaturated polyester resin or vinyl ester resin, positionedon a carrier sheet that has a non-adhering surface. A second,non-adhering carrier sheet containing a second layer of polymer film maybe positioned onto the chopped glass fibers in an orientation such thatthe second polymer film contacts the chopped glass bundles and forms asandwiched material of polymer film-chopped glass-polymer film. Thissandwiched material may then be kneaded with rollers such as compactionrollers to substantially uniformly distribute the polymer resin matrixand glass fiber bundles throughout the resultant SMC material. As usedherein, the term “to substantially uniformly distribute” means touniformly distribute or to nearly uniformly distribute. The SMC materialmay then be stored for 2–3 days to permit the resin to thicken andmature.

Once the SMC material has reached the target viscosity, the SMC materialmay be cut into charges and placed into a mold having the desired shapeof the final product. The mold is heated to an elevated temperature andwhen it is closed, it is raised to a high pressure. This combination ofhigh heat and high pressure causes the SMC material to flow and fill outthe mold. The matrix resin then crosslinks or cures to form the finalthermoset molded composite part. Exemplary molded composite parts formedby fibers sized with the inventive sizing composition include exteriorautomotive body parts and structural automotive body parts. The exteriorautomotive body parts may contain approximately 25–30% glass content andstructural automotive body parts may contain approximately 30–60% glasscontent.

The sizing composition of the present invention provides improvedwetting characteristics. Faster wetting of the glass fibers results ingreater productivity in-line and the ability to produce a larger amountof SMC material per hour. In addition, faster wetting of the glassfibers results in an SMC material that contains fewer dry glass fibers.Fewer dry glass fibers in the SMC material in turn results in areduction in the number of defects that may occur during the molding ofthe composite part and a reduction in the manufacturing costs associatedwith the production of composite parts formed from glass fibers sizedwith the sizing composition.

Having generally described this invention, a further understanding canbe obtained by reference to certain specific examples illustrated belowwhich are provided for purposes of illustration only and are notintended to be all inclusive or limiting unless otherwise specified.

EXAMPLES Example 1

Class A SMC Resin Formulations

Sizing compositions containing a silanated polyvinyl acetate, anepoxidized polyvinyl acetate, a modified epoxy emulsion, A-1100, andEmery 6760L with varying film former ratios were made and tested todetermine the wet-out rating in a Class A resin system used for exteriorautomotive body panels. The wet-out rating is a subjective estimate ofthe percent of non-wet fibers present in an SMC line wetting test. TheSMC line wetting test included placing an SMC resin on a bottom,non-adhering layer, placing dry chopped glass sized with an inventivesizing composition onto the SMC resin, and then visually rating how wellthe SMC resin wets up through the chopped glass bundles. The less dryglass visualized on the top of the chopped glass bundles, the lower thewet-out rating and the better the wetting. Standard rovings 973C-AA,905A-AB, and 973C-AB sized with a polyester emulsion, a polyvinylacetate, and a modified epoxy emulsion were evaluated as controls. Theratios of the film formers and the results are set forth in Table 2.

TABLE 2 Wetting Results in Class A SMC Resin System SMC Wet Out FilmFilm Film % Rating Trial Ratio Former 1 Former 2 Former 3 LOI (%) Mix1-1 90/5/5 silanated PVAc epoxidized PVAc modified epoxy 1.62 35emulsion Mix 2-1 50/45/45 silanated PVAc epoxidized PVAc modified epoxy1.38 35 emulsion Mix 3-1 50/5/45 silanated PVAc epoxidized PVAc modifiedepoxy 1.34 80 emulsion Mix 4-1 70/25/5 silanated PVAc epoxidized PVAcmodified epoxy 1.49 25 emulsion Mix 5-1 70/5/25 silanated PVAcepoxidized PVAc modified epoxy 1.56 35 emulsion Mix 6-1 50/25/25silanated PVAc epoxidized PVAc modified epoxy 1.35 45 emulsion Mix 7-163/18/18 silanated PVAc epoxidized PVAc modified epoxy 1.55 35 emulsionMix 1-2 90/5/5 silanated PVAc epoxidized PVAc modified epoxy 1.62 30emulsion Mix 2-2 50/45/5 silanated PVAc epoxidized PVAc modified epoxy1.38 25 emulsion Mix 3-2 50/5/45 silanated PVAc epoxidized PVAc modifiedepoxy 1.34 80 emulsion Mix 4-2 70/25/5 silanated PVAc epoxidized PVAcmodified epoxy 1.49 20 emulsion Mix 5-2 70/5/25 silanated PVAcepoxidized PVAc modified epoxy 1.56 30 emulsion Mix 6-2 50/25/25silanated PVAc epoxidized PVAc modified epoxy 1.35 45 emulsion Mix 7-263/18/18 silanated PVAc epoxidized PVAc modified epoxy 1.55 35 emulsionMix 8 90/5/5 silanated PVAc epoxidized PVAc modified epoxy 1.77 10emulsion Mix 9 70/5/25 silanated PVAc epoxidized PVAc modified epoxy1.55 40 emulsion Mix 10 63/18/18 silanated PVAc epoxidized PVAc modifiedepoxy 1.52 20 emulsion Mix 11 63/18/18 silanated PVAc epoxidized PVAcmodified epoxy 1.49 15 emulsion Mix 12 63/18/18 silanated PVAcepoxidized PVAc modified epoxy 1.52 35 emulsion Mix 13 90/5/5 silanatedPVAc epoxidized PVAc modified epoxy 1.67 40 emulsion Mix 14 63/18/18silanated PVAc epoxidized PVAc modified epoxy 1.41 40 emulsion Mix 1570/5/25 silanated PVAc epoxidized PVAc modified epoxy 2.04 35 emulsionMix 16 63/18/18 silanated PVAc epoxidized PVAc modified epoxy 1.94 30emulsion Mix 17 70/5/25 silanated PVAc epoxidized PVAc modified epoxy2.03 35 emulsion Mix 18 63/18/18 silanated PVAc epoxidized PVAc modifiedepoxy 1.94 30 emulsion Control 1 973 K- polyester polyvinyl acetatemodified epoxy 1.90 45 (973C-AA) Fiber emulsion emulsion Control 2 905K- polyester polyvinyl acetate modified epoxy 1.55 85 (905A-AB) Fiberemulsion emulsion Control 3 973 M- polyester polyvinyl acetate modifiedepoxy 1.93 35 (973C-AB) Fiber emulsion emulsion

Initially, it was determined that Control 3 had the best SMC wet-outrating of the three standard rovings. Next, the SMC wet-out percent ofControl 3 was compared to the SMC wet-out percent of the fibers sizedwith the inventive sizing compositions. In this experiment, an SMCwet-out rating difference of 10 percent or greater was considered to bea visually significant difference and to demonstrate improved wettingcharacteristics. As can be seen in Table 2, Mix 4-1, 4-2, Mix 10, andMix 11 (film forming ratios 70/25/5, 70/25/5, 63/18/18, and 63/18/18respectively) had a wet-out rating with a difference of 10% or greaterthan the wet out rating of Control 3. It was concluded that ratios70/25/5 and 63/18/18 for the film formers of the inventive sizingcomposition demonstrated improved wetting characteristics in Class Aresin SMC systems.

Example 2

Structural SMC Formulations

Sizing compositions containing a silanated polyvinyl acetate, anepoxidized polyvinyl acetate, a modified epoxy emulsion, A-1100, andEmery 6760L with varying film former ratios were made and tested todetermine the wet-out rating in a structural SMC resin system used forstructural automotive body parts. The wet-out rating is a subjectiveestimate of the percent of non-wet fibers present in an SMC line wettingtest. The SMC line wetting test included placing an SMC resin on abottom, non-adhering layer, placing dry chopped glass sized with aninventive sizing composition onto the SMC resin, and then visuallyrating how well the SMC resin wets up through the chopped glass bundles.The less dry glass visualized on the top of the chopped glass bundles,the lower the wet-out rating and the better the wetting. Standardrovings 973C-AA, 905A-AB, and 973C-AB sized with a polyester emulsion, apolyvinyl acetate, and a modified epoxy emulsion were evaluated ascontrols. The ratios of the film formers and the results are set forthin Table 3.

TABLE 3 Wetting Results in Structural SMC Resin System SMC Wet Out FilmFilm Film % Rating Trial Ratio Former 1 Former 2 Former 3 LOI (%) Mix1-1 90/5/5 silanated PVAc epoxidized PVAc modified epoxy 1.62 50emulsion Mix 2-1 50/45/45 silanated PVAc epoxidized PVAc modified epoxy1.38 30 emulsion Mix 3-1 50/5/45 silanated PVAc epoxidized PVAc modifiedepoxy 1.34 20 emulsion Mix 4-1 70/25/5 silanated PVAc epoxidized PVAcmodified epoxy 1.49 25 emulsion Mix 5-1 70/5/25 silanated PVAcepoxidized PVAc modified epoxy 1.56 15 emulsion Mix 6-1 50/25/25silanated PVAc epoxidized PVAc modified epoxy 1.35 5 emulsion Mix 7-163/18/18 silanated PVAc epoxidized PVAc modified epoxy 1.55 10 emulsionMix 1-2 90/5/5 silanated PVAc epoxidized PVAc modified epoxy 1.62 40emulsion Mix 2-2 50/45/5 silanated PVAc epoxidized PVAc modified epoxy1.38 20 emulsion Mix 3-2 50/5/45 silanated PVAc epoxidized PVAc modifiedepoxy 1.34 15 emulsion Mix 4-2 70/25/5 silanated PVAc epoxidized PVAcmodified epoxy 1.49 20 emulsion Mix 5-2 70/5/25 silanated PVAcepoxidized PVAc modified epoxy 1.56 10 emulsion Mix 6-2 50/25/25silanated PVAc epoxidized PVAc modified epoxy 1.35 10 emulsion Mix 7-263/18/18 silanated PVAc epoxidized PVAc modified epoxy 1.55 10 emulsionMix 8 90/5/5 silanated PVAc epoxidized PVAc modified epoxy 1.77 30emulsion Mix 9 70/5/25 silanated PVAc epoxidized PVAc modified epoxy1.55 5 emulsion Mix 10 63/18/18 silanated PVAc epoxidized PVAc modifiedepoxy 1.52 3 emulsion Mix 11 63/18/18 silanated PVAc epoxidized PVAcmodified epoxy 1.49 20 emulsion Mix 12 63/18/18 silanated PVAcepoxidized PVAc modified epoxy 1.52 10 emulsion Mix 13 90/5/5 silanatedPVAc epoxidized PVAc modified epoxy 1.67 20 emulsion Mix 14 63/18/18silanated PVAc epoxidized PVAc modified epoxy 1.41 30 emulsion Mix 1570/5/25 silanated PVAc epoxidized PVAc modified epoxy 2.04 30 emulsionMix 16 63/18/18 silanated PVAc epoxidized PVAc modified epoxy 1.94 20emulsion Mix 17 70/5/25 silanated PVAc epoxidized PVAc modified epoxy2.03 25 emulsion Mix 18 63/18/18 silanated PVAc epoxidized PVAc modifiedepoxy 1.94 20 emulsion Control 1 973 K- polyester polyvinyl acetatemodified epoxy 1.90 35 (973C-AA) Fiber emulsion emulsion Control 2 905K- polyester polyvinyl acetate modified epoxy 1.55 30 (905A-AB) Fiberemulsion emulsion Control 3 973 M- polyester polyvinyl acetate modifiedepoxy 1.93 30 (973C-AB-1) Fiber emulsion emulsion

Initially, it was determined that Controls 2 and 3 had the lowest SMCwet-out rating of the three standard rovings tested. A comparison of theSMC wet-out percent of Controls 2 and 3 and the SMC wet-out percentagesof the fibers sized with the inventive sizing compositions was thenmade. An SMC wet-out rating difference of 10 percent or greater wasconsidered to be a visually significant difference and to demonstrateimproved wetting characteristics. As can be seen in Table 3, Mix 3-1(ratio 50/5/45), Mix 5-1 (ratio 70/5/25), Mix 6-1 (ratio 50/25/25), Mix7-1 (ratio 63/18/18), Mix 3-2 (ratio 50/5/45), Mix 4-2 (ratio 70/25/5),Mix 5-2 (ratio 70/5/25), Mix 6-2 (ratio 50/25/25), Mix 7-2 (ratio63/18/18), Mix 9 (ratio 70/5/25), Mix 10 (ratio 63/18/18), Mix 11 (ratio63/18/18), Mix 12 (ratio 63/18/18), Mix 16 (ratio 63/18/18), and Mix 18(ratio 63/18/18) had a wet-out rating with a difference of greater than10% compared to the controls. It was therefore concluded that ratios50/5/45, 70/25/5, 70/5/25, 50/25/25, and 63/18/18 for the film formersof the inventive sizing composition demonstrated improved wettingcharacteristics in structural SMC resin systems.

The foregoing description of the specific embodiments will so fullyreveal the general nature of the invention that others can, by applyingknowledge within the skill of the art (including the contents of thereferences cited herein), readily modify and/or adapt for variousapplications such specific embodiments, without undue experimentation,without departing from the general concept of the present invention.Therefore, such adaptations and modifications are intended to be withinthe meaning and range of equivalents of the disclosed embodiments, basedon the teaching and guidance presented herein. It is to be understoodthat the phraseology or terminology herein is for the purpose ofdescription and not of limitation, such that the terminology orphraseology of the present specification is to be interpreted by theskilled artisan in light of the teachings and guidance presented herein,in combination with the knowledge of one of ordinary skill in the art.

The invention of this application has been described above bothgenerically and with regard to specific embodiments. Although theinvention has been set forth in what is believed to be the preferredembodiments, a wide variety of alternatives known to those of skill inthe art can be selected within the generic disclosure. The invention isnot otherwise limited, except for the recitation of the claims set forthbelow.

1. A sizing composition for glass fibers comprising: a film formingpolymer component that includes: a silanated polyvinyl acetate; anepoxidized polyvinyl acetate; and a modified epoxy emulsion; at leastone silane coupling agent; and one or more lubricants; wherein saidsilanated polyvinyl acetate is present in said film forming polymercomponent in an amount that is greater than said epoxidized polyvinylacetate and said modified epoxy emulsion.
 2. The sizing composition ofclaim 1, wherein said film forming polymer component has a silanatedpolyvinyl acetate:epoxidized polyvinyl acetate:modified epoxy emulsionratio of 75:25:5.
 3. The sizing composition of claim 1, wherein saidfilm forming polymer component has a silanated polyvinylacetate:epoxidized polyvinyl acetate:modified epoxy emulsion ratio of50:25:25.
 4. The sizing composition of claim 1, wherein said filmforming polymer component has a silanated polyvinyl acetate:epoxidizedpolyvinyl acetate:modified epoxy emulsion ratio of 63:18:18.
 5. Thesizing composition of claim 1, further comprising a pH adjusting agent.6. The sizing composition of claim 1, wherein said modified epoxyemulsion is selected from the group consisting of an amine-modifiedepoxy emulsion and an epoxy ester emulsion.
 7. A reinforcing fiberproduct comprising one or more strands of a reinforcing fiber materialat least partially coated with a sizing composition comprising: a filmforming polymer component including: a silanated polyvinyl acetate; anepoxidized polyvinyl acetate; and a modified epoxy emulsion; at leastone silane coupling agent; and one or more lubricants, wherein saidsilanated polyvinyl acetate is the major constituent in said filmforming polymer component.
 8. The reinforcing fiber product of claim 7,wherein said film forming polymer component has a silanated polyvinylacetate:epoxidized polyvinyl acetate:modified epoxy emulsion ratio of75:25:5.
 9. The reinforcing fiber product of claim 7, wherein said filmforming polymer component has a silanated polyvinyl acetate:epoxidizedpolyvinyl acetate:modified epoxy emulsion ratio of 50:25:25.
 10. Thereinforcing fiber product of claim 7, wherein said film forming polymercomponent has a silanated polyvinyl acetate:epoxidized polyvinylacetate:modified epoxy emulsion ratio of 63:18:18.
 11. The reinforcingfiber product of claim 7, wherein said modified epoxy emulsion isselected from the group consisting of an amine-modified epoxy emulsionand an epoxy ester emulsion.
 12. The reinforcing fiber product of claim7, wherein said sizing composition further comprises a pH adjustingagent.
 13. The reinforcing fiber product of claim 7, wherein saidreinforcing fiber is selected from the group consisting of glass fibers,modified glass fibers, carbon fibers and synthetic polymer fibers. 14.The reinforcing fiber product of claim 13, wherein said reinforcingfiber product is in the form of a roving.
 15. A reinforced compositearticle comprising a plurality of glass fibers sized with a sizingcomposition that includes: a film forming polymer component including: asilanated polyvinyl acetate; an epoxidized polyvinyl acetate; and amodified epoxy emulsion; at least one silane coupling agent; and one ormore lubricants, wherein said silanated polyvinyl acetate is the majorconstituent in said film forming polymer component.
 16. The compositearticle of claim 15, wherein said film forming polymer component has asilanated polyvinyl acetate:epoxidized polyvinyl acetate:modified epoxyemulsion ratio selected from the group consisting of 75:25:5, 50:25:25and 63:18:18.
 17. The composite article of claim 16, wherein saidmodified epoxy emulsion is selected from the group consisting of anamine-modified epoxy emulsion and an epoxy ester emulsion.
 18. Thecomposite article of claim 17, wherein said sizing composition furthercomprises a pH adjuster.
 19. The composite article of claim 16, whereinsaid composite article has a form of a structural body part of anautomobile.
 20. A sizing composition for glass fibers comprising: a filmforming polymer component that includes: a silanated polyvinyl acetate;an epoxidized polyvinyl acetate; and a modified epoxy emulsion; at leastone silane coupling agent; and one or more lubricants; wherein said filmforming polymer component is present in said sizing composition in aratio selected from the group consisting of 75:25:5, 50:25:25, 63:18:18,50:5:45 and 70:5:25 of said silanated polyvinyl acetate, said epoxidizedpolyvinyl acetate, and said modified epoxy emulsion respectively. 21.The sizing composition of claim 20, wherein said at least one silanecoupling agent is present in said sizing composition in an amount from0.05–0.20% active solids.
 22. The sizing composition of claim 20,wherein said one or more lubricants is present in said sizingcomposition in an amount from 0.025–0.010% active solids.
 23. The sizingcomposition of claim 20, wherein said sizing composition furthercomprises at least one additive selected from the group consisting ofanti-static agents, dyes, oils, fillers, thermal stabilizers, biocides,anti-foaming agents, anti-oxidants, dust suppression agents and wettingagents, said at least one additive being present in said sizecomposition in an amount of not more than about 5.0% of the total weightof said sizing composition.